1. Field of the Invention
This invention relates to a novel process for the production of aromatic polyesters utilizing mixed anhydrides as intermediates.
2. Description of Related Art
The following information is disclosed in accordance with the terms of 37 CFR 1.56, 1.97 and 1.98.
U.S. Pat. No. 4,680,372 issued July 14, 1987 to Rosenfeld discloses the production of aromatic polyesters of a bisphenol, e.g. bisphenol A, and an aromatic dicarboxylic acid, e.g., terephthalic and/or isophthalic acid, by melt polymerizing the bisphenol and the acid or a diester thereof in the presence of phenyl benzoate.
U.S. Pat. No. 4,296,232 issued Oct. 20, 1981 to Maresca et al. discloses the preparation of polyarylates, i.e., aromatic polyesters, by reacting a diester of a dihydric phenol, e.g., bisphenol A, with an aromatic dicarboxylic acid, e.g., a mixture of terephthalic and isophthalic acids, in the presence of a diphenyl ether compound and a magnesium catalyst.
U.S. Pat. No. 4,281,099 issued July 28, 1981 to Maresca, discloses a process similar to that of U.S. Pat. No. 4,296,232 described previously except that a stabilizing amount of an aromatic phenol, e.g., p-phenylphenol, is added to the polyarylate to eliminate residual anhydride linkages.
Belgian Patent No. 549,667, published Nov. 16, 1956, C.A. 52:5033g (1958) discloses a process for the preparation of polyethylene terephthalate (PET) comprising the steps of forming a mixed anhydride of terephthalic and acetic acids, heating the latter mixed anhydride as a solution in 1-methylnaphthalene to distill off acetic acid and acetic anhydride and obtain a polymeric mixed anhydride containing 96% of terephthalic moieties, and reacting the latter polymeric anhydride with ethylene glycol in the presence of antimony trioxide to obtain PET.